Today active research and development are carried out on various display devices. Of the devices, organic electroluminescence (EL) devices (hereinafter, referred to as EL devices, or luminescent devices) can give luminescence having high brightness at low voltage, and therefore attention is paid to the devices as promising display devices.
JP-A-10-59943 (“JP-A” means unexamined published Japanese patent application) discloses a compound having an azepine structure, which is employable in an organic electroluminescent device. However, the structures disclosed are severely limited.
Generally, further, a compound having an azepine structure requires multi-steps for a method of synthesis thereof. JP-A-2001-97953 discloses a synthesis method using no special reagent, and although this method is to derive a compound having an azepine structure from commercially available materials, it requires a multi-step process. As such, there has been demanded for a method of synthesizing a compound having an azepine structure by fewer steps.